Method of manufacturing reinforced paper



Feb. 28, 1939.

Filed April 25', 1956 INV ENTOR ATTORNEY Patented Feb. 28, 1939 UNITED STATES PATENT OFFICE METHOD OF MANUFACTURING REIN- FORCED PAPER William H. Millspaugh, Catawba Island, Ohio,

assignor to Sandusky Foundry & Machine Company, Sandusky, Ohio, a corporation of Ohio Application April 25, 1936, Serial No. 76,410

2 Claims.

The invention to be hereinafter described relates to reinforced paper.

There is a very great commercialneed for a tough strong paper having a high degree of tear resistance, for wrapping parcels and for making bags of different character. For such and many other purposes the paper must withstand many sudden hard strains and tough treatment.

It is the principal object of the present invention to provide a novel method and machine for economically producing in one operation a strong iinishedreinforced sheet in which the paper and fabric are securely bonded together.

Another object of the invention resides in the novel product resulting from the method herein set forth.

Other objects and advantages of the invention will be apparent from the following description and from the accompanying drawing, in which-' Fig. 1 is a diagrammatic side elevation of a forming apparatus, embodying the present invention;

Fig. 2 is a magnified cross section of a piece of reinforcing fabric applied to one side of a wet web;

Fig. 3 is a likeA view of the finished reinforced sheet; and

Fig. 4 is a modified form of apparatus in which the reinforcing web is led through the stock vat.

As shown in Fig. 1, the apparatus embodies one or more suction forming rolls and adjacent Stock vats of the character disclosed in prior Patents No. 1,718,574 and No. 1,748,360. The apparatus comprises two head boxes or stock vats I and I I and cooperating forming rolls I2 and I3, forming wires I4 and I5`and suitable carrying and transfer rolls, all of which are now well understood in the art and need not be further described here. The upwardly moving portions of the forming rolls are subjected to vacuum in the region of the head boxes where the paper pulp is deposited.

In accordance with the present invention, means are provided for supplying a sheet of cloth fabric orthe like 2| to the paper web on one of the forming wires, and, if desired, for coating the fabric sheet before it is applied to the Web on the forming wire with a suitable fluid material having the desired adhesive characteristics so that the fabric may be very intimately bonded with the pulp fibers. Adjacent the paper forming apparatus suitable supporting means are provided for a roll 22 of cloth fabric 2|. The fabric is supplied through spreader rolls 23 by which it is conthe spreader rolls the cloth fabric is led to the upper side of the wet paper web on the forming Wire I4 at a point just beyond the forming area on the suction roll. It travels with the forming wire and the paper web thereon, the adhesion and frictional engagement of the layers being suiiicient to draw the fabric from the roll 22 and through the spreading rolls, etc.

`'I'he reinforcing fabric 2| is thus applied to the web of paper pulp on the roll I2 before leaving the roll and while the web of paper is still wet, so that the reinforcing fabric is forced slightly into the paper ber mass by reason o-f the slight frictional resistance to forward movement of the reinforcing fabric. This action causes a very thorough union of the reinforcing fabric with the wet paper bers, as illustrated in Fig. 2, some of the fibers being caused to move up into the interstices between adjacent threads of the fabric at the time, or just after, the paper web on the forming roll is subjected to the action of vacuum at the region A.

Before applying the reinforcing fabric 2| to the paper web the fabric may, if desired, be led through the nip of coating rolls 24, the lower coating roll dipping into a tank 25 containing a quantity of uid or semi-fluid material having adhesive characteristics and preferably of a moisture repelling nature. The material of the bathl may be of such character that it becomes tacky and very adhesive, especially at high temperatures. As the cloth fabric passes over the lower coating roll it is given an application of the coating material, the squeeze action of the two rolls preventing an excess of material being supplied. Latex or similar fluid may be used as a coating since the properties of such substance are admirably adapted for the purpose intended. It will be understood that the container or tank 25 is maintained at a suitable temperature so that the coating material is in a fluid condition. After the application of the coated or uncoated reinforcing fabric to the paper web on the forming roll |2 the combined sheet may be carried by the wire I4 to the point 26 where the combined sheet is transferred,` preferably by suction, to a wet paper web produced on the forming roll I3, the fabric side of the combined sheet being applied to the outer surface of the second paper web, so as to incorporate the reinforcement between two outer layers of paper. The reinforced paper web thus obtained, and which has been shown in section in Fig. 3, is then supplied to the driers and its constituent parts are securely bonded together by the heat and pressure of the driers. Any bonding material with which the reinforcing fabric was coated is rendered tacky and adhesive by the drying and heating action. The product is a single composite, reinforced sheet of a flexible character.

In accordance with the modified form of apparatus illustrated in Fig.,4, the reinforcing fabric sheet may be applied to the mat of paper fibers on the forming roll before the forming wire reaches the end of the forming zone. The woven fabric 30 is thus supplied through suitable spreader rolls, not shown, over an upper guide roll 3| mounted above the head-box partition, down through the paper stock and around and under the submerged guide roll 32. The fabric then passes through the paper stock onto the adjacent forming Wire 33 on forming roll 34 at a point a suitable distance below the line at which the roll emerges from the stock.

The reinforcing fabric cloth web is thus in contact with and covers an appreciable segment or arc of the forming roll below the surface of the stock, and is acted upon by the forming vacuum. A partial layer of fibers will be formed on the making wire, and then the reinforcing fabric will be applied to the outer surface of this partially formed layerrof paper fibers. During the continued rotation of the forming roll and after the reinforcing fabric is applied to the partially formed layer of fibers, the suction of the forming roll continues to act so as to deposit additional paper fibers on the outer side of the reinforcing fabric as the vacuum continues to draw the flbers of the stock intimately about, over and through the spaces between the crossed woven threads of the fabric. The fabric threads are thus straddled by innumerable paper stock fibers which are matted intimately together on and in the body of the fabric, the matted fibers securely interlocking the layers of paper fibers which are on the two opposite sides of the fabric. The sheet which emerges from thepaperstock vat is a fabric reinforced paper web in which the fabric and the paper fibers are thoroughly and intimately incorporated as a component part thereof.

While the integrally united fabric and paper fibers coming from the forming roll 34 may be'subjected to the heat and pressure of the dri'ers to produce the finished product, an outer layer of paper web may be applied to the composite web that is formed as just above mentioned. A second headbox and asecond forming roll may therefore be provided and the paper; web it produces is applied to the outer layer of the composite formation produced on the forming wire 33. to heat in the driers, forming the composite web into an integrally united mass of paper fibers and reinforcing strong fabric. The product is made as a single continuous formation, the apparatus being quite simple. The product is adapted to be bent without disturbing the intimate Vand integral formation of its constituent elements, and may be of any desired density dependent upon the pressure to which the composite web is subjected in the driers.

While the method herein described, and the forms of apparatus for carrying the method into effect, and the product produced thereby, constitute preferred embodiments of the invention, it is to be understood that the invention is not limited precisely lthereto, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. The method of manufacturing reinforced paper comprising forming a web of paper by vacuum formation on a. forming roll, feeding a reinforcing fabric onto said paper web! after emergence of the web but before it leaves the forming roll, curving the fabric partly around the roll while the outer side of the fabric is unconfined to fill the interstices between the threads of the fabric by paper bers, removing the composite sheet from the forming roll, and subjecting to heat and pressure.

2. The method of manufacturing reinforced paper comprising separately forming a plurality of webs of paper by vacuum formation on forming rolls, feeding therebetween a reinforced fabric, supplying coating material to said fabric during such feeding, applying the fabric while unconfined to the outer surface of one of the webs after emergence. of such web from the stock supply and before such web leaves the forming roll, and heating and pressing the composite sheet.

WILLIAM H. MILLSPAUGH.

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The resultant web is then subjected {f "cERTIFIcATE 0F"coma'EczTIolL Patent No. 2,ll4B,LL9O. l l February 28., 21.959@I wILLmnmnImsPAUem .It is hereby lc eI-tzlfied that error appears in the4 printed' specification of the 'above numbered pate-nt'requirngacorection asv-follows: Page 2 second f column, linelhZ, qiai'm 2, for the 'word're`infoced" .readreinforcingg and that the said'Letters Patent should be read with this Ycorreotion therein 4 that the `samie-may conform to the record'o'f tle 4oase irithe- Patent Office.

Signed and sealed this lth day of April, A, D. '1959.

Henry Van Arsdale ($69.1) Acting` Commissioner 'ofatentm 

